Prior to 1978, conduction cooled capacitors, used for example in induction heaters, were connected between two plates on either side of the capacitor. FR2360975 describes a sideways cooled power capacitor that comprises dielectric layers such as silvered mica, disposed between two metal plate electrodes and encased in an insulating material e.g. epoxy resin. Each plate is extended by a flange parallel to the plane of the dielectric layers. The flanges have tabs perpendicular to the plates for mounting onto water-cooled bus bars.
U.S. Pat. No. 5,953,201 discloses sideways conduction-cooled capacitors with one or more bores extending through each of the capacitor electrodes for receiving the capacitor fastening bolts. This design for a sideways cooled capacitor uses solid copper electrodes with contact surfaces replacing the fixing legs used in previous designs. It also makes use of wound polypropylene film capacitor elements and is mounted using two through holes. However, this design has the disadvantage that machining is required for the solid electrodes which also need a large quantity of copper, thus making the manufacturing process expensive.
U.S. Pat. No. 7,002,789 discloses a capacitor assembly mountable on bus bars, has two or more capacitive elements arranged between opposing L-shaped sections of two brackets including “arcuate” sections. The capacitive elements are arranged between a pair of brackets having an “arcuate” bracket section between a pair of L-shaped sections. Each of the capacitive elements has one end contacting capacitor seating surface of one bracket, and the other end contacting with the seating surfaces of the other bracket. However, the complexity of the “arcuate” sections of these brackets increases the cost.
All the methods described above have not yet provided satisfactory solutions to the problem of manufacturing a power capacitor which is compact, lightweight and cost effective while allowing effective cooling.
It is therefore an object of the present invention to provide a method for manufacturing a conduction cooled power capacitor which is compact, lightweight and cost effective while allowing effective cooling.
Other objects and advantages of the invention will become apparent as the description proceeds.